Method to estimate the current datapacket rate of a virtual connection, a feedback mechanism using said method and device, switching node and destination node realizing said method

Abstract

A method is described to estimate the current datapacket rate CCR i called herein current cell rate, of a connection out of a plurality of connections which are carrying datapackets via a multiplexed transmission channel in a communication network. The method includes the steps of storing in a buffer (B) incoming datapackets of the connections, determining the total number of datapackets BC TO in the buffer (B), determining the number of datapackets of the connection BC i in the buffer (B), measuring an aggregate input datapacket rate C IN of the buffer and estimating the current datapacket rate CCR i via the formulae: ##EQU1##

What is claimed is: 
     
       1. A method of estimating, in a node (SN) of a communication network, the current datapacket rate CCRi of one out of a plurality of connections passing through or arriving at said node (SN) and carrying datapackets transmitted via a multiplexed transmission channel in said communication network wherein said method comprises the steps of: a) storing in a buffer (B) of said node (SN) incoming datapackets of said connections;   b) determining the total number of datapackets BC TO  in said buffer (B);   c) determining the number of datapackets of said connection BC i  in said buffer (B);   d) measuring an aggregate input datapacket rate C IN  of said buffer (B); and   e) estimating said current datapacket rate CCR i , via the equation: ##EQU10##   
     
     
       2. A method according to claim 1, wherein step d of said method is implemented by counting the number of datapackets which enter said buffer (B) during a predetermined period. 
     
     
       3. A method according to claim 1, characterised in that said current datapacket rate CCR i  of said connection is estimated: each time a datapacket comes in said buffer (B); or   each time a datapacket goes out said buffer (B); or   each time a datapacket comes in or goes out said buffer (B).   
     
     
       4. A feedback mechanism for use in a communication network supporting services including the available bit rate service (ABR) in an asynchronous transfer mode (ATM) environment, said communication network including N source nodes (S 1 , . . . , S i , . . . , S N ) and a destination node (D) between which a plurality of connections carrying datapackets via a multiplexed transmission channel are established, said feedback mechanism making use of the current datapacket rate CCR i  of one connection out of said plurality of connections to determine network feedback information for said connection usable in a resource management datapacket (RM), and wherein said feedback mechanism estimates said current datapacket rate CCR i  by performing the steps of: a) storing in a buffer (B) of said node (SN) incoming datapackets of said connections;   b) determining the total number of datapackets BC TO  in said buffer (B);   c) determining the number of datapackets of said connection BC i  in said buffer (B);   d) measuring an aggregate input datapacket rate C IN  of said buffer (B); and   e) estimating said current datapacket rate CCR i , via the equation: ##EQU11##     
     
     
       5. A feedback mechanism for use in a communication network supporting services including the available bit rate service (ABR) in an asynchronous transfer mode (ATM) environment, said communication network including N source nodes (S 1 , . . . , S i , . . . , S N ) and a destination node (D) between which a plurality of connections carrying datapackets via a multiplexed transmission channel are realised and including buffer means which are storing incoming datapackets of said connections, said feedback mechanism making use of the ratio of the current datapacket rate CCR i  of one connection out of said plurality of connections and a value Z representing an overload factor of said buffer means which is proportional to the aggregate input datapacket rate C IN  of said buffer means to determine network feedback information for said connection usable in a resource management datapacket (RM), characterised in that said feedback mechanism calculates said ratio by performing the steps of: a) storing in said buffer means incoming datapackets of said connections;   b) determining the total number of datapackets BC TO  in said buffer means;   c) determining the number of datapackets of said connection BC i  in said buffer means; and   calculating said ratio proportional to said number of datapackets of said connection BC i , and inversely proportional to said total number of datapackets BC TO .   
     
     
       6. A device adapted to estimate the current datapacket rate CCR i  of one connection out of a plurality of connections carrying datapackets via a multiplexed transmission channel in a communication network characterised in that said device includes a buffer (B) to store incoming datapackets of said connections, register means (REG) to register a first number BC TO  representing the total number of datapackets stored in said buffer (B) and a second number BC i  representing the number of datapackets of said connection stored in said buffer (B), datapacket rate measuring means (M) for measuring the aggregate input datapacket rate C IN  of said buffer (B) and calculating means (CALC) for estimating said current datapacket rate CCR i  via the formulae: ##EQU12## 
     
     
       7. A device adapted to estimate the current datapacket rate CCR i , according to claim 6, characterised in that said measuring means (M) includes counter means to count the number of datapackets which enter said buffer (B) during a predetermined period and clock means to determine said predetermined period. 
     
     
       8. A switching node (SN) included in a communication network for use by services including according to the available bit rate (ABR) service in an asynchronous transfer mode (ATM) environment, said communication network also including N source nodes (S 1 , . . . , S i , . . . , S N ) and a destination node (D) between which a plurality of connections carrying datapackets via a multiplexed transmission channel are realised, said switching node (SN) including means to determine from the current datapacket rate CCR i  of one connection out of said plurality of connections, network feedback information for said connection usable in a resource management datapacket (RM) and characterised in that said switching node (SN) includes a device adapted to estimate the current datapacket rate CCR i , of one connection out of a plurality of connections carrying datapackets via a multiplexed transmission channel in a communication network, and further characterised in that said device includes a buffer (B) to store incoming datapackets of said connections, register means (REG) to register a first number BC TO  representing the total number of datapackets stored in said buffer (B) and a second number BC i  representing the number of datapackets of said connection stored in said buffer (B), datapacket rate measuring means (M) for measuring the aggregate input datapacket rate C IN  of said buffer (B) and calculating means (CALC) for estimating said current datapacket rate CCR i  via the equation: ##EQU13## 
     
     
       9. A switching node (SN) according to claim 8, further characterized in that said measuring means (M) includes counter means to count the number of datapackets which enter said buffer (B) during a predetermined period and clock means to determine said predetermined period. 
     
     
       10. A switching node (SN) included in a communication network for use by services including according to the available bit rate (ABR) service in an asynchronous transfer mode (ATM) environment, said communication network also including N source nodes (S 1 , . . . , S i , . . . , S N ) and a destination node (D) between which a plurality of connections carrying datapackets via a multiplexed transmission channel are realised, said switching node (SN) including buffer means to store incoming datapackets of said connections and including means to determine from the ratio of the current datapacket rate CCR i  of one connection out of said plurality of connections and a value Z such as representing an overload factor of said buffer means which is proportional to the aggregate input datapacket rate (C IN ) of said buffer means, network feedback information for said connection usable in a resource management datapacket (RM), characterised in that said switching node (SN) includes register means (REG) to register a first number BC TO  representing the total number of datapackets stored in said buffer means, and a second number BC i  representing the number of datapackets of said connection stored in said buffer means and calculating means (CALC) to calculate said ratio proportional to said number of datapackets of said connection BC i  and inversely proportional to said total number of datapackets BC TO . 
     
     
       11. A destination node (D) included in a communication network for use by services including the available bit rate (ABR) in an asynchronous transfer mode (ATM) environment, between N source nodes also included in said communication network and said destination node (D) a plurality of connections carrying datapackets via a multiplexed transmission channel are realised, said destination node (D) including means to determine from the current datapacket rate CCR i , of one connection out of said plurality of connections to determine network feedback information for said connection usable in a resource management datapacket (RM), characterised in that said destination node (D) includes a device adapted to estimate the current datapacket rate CCR i , of one connection out of a plurality of connections carrying datapackets via a multiplexed transmission channel in a communication network, and further characterised in that said device includes a buffer (B) to store incoming datapackets of said connections, register means (REG) to register a first number BC TO  representing the total number of datapackets stored in said buffer (B) and a second number BC i  representing the number of datapackets of said connection stored in said buffer (B), datapacket rate measuring means (M) for measuring the aggregate input datapacket rate C IN  of said buffer (B) and calculating means (CALC) for estimating said current datapacket rate CCR i  via the equation: ##EQU14## 
     
     
       12. A destination node (D) according to claim 11, further characterized in that said measuring means (M) includes counter means to count the number of datapackets which enter said buffer (B) during a predetermined period and clock means to determine said predetermined period. 
     
     
       13. A destination node (D) included in a communication network for use by services including the available bit rate (ABR) service in an asynchronous transfer mode (ATM) environment, between N source nodes also included in said communication network and said destination node (D) between which a plurality of connections carrying datapackets via a multiplexed transmission channel are realised, said destination node (D) including buffer means to store incoming datapackets of said connections and including means to determine, from the ratio of the current datapacket rate CCR i  of one connection out of said plurality of connections and a value Z representing an overload factor of said buffer means which is proportional to the aggregate input datapacket rate (C IN ) of said buffer means network, feedback information for said connection usable in a resource management datapacket (RM), characterised in that said destination node (D) includes register means (REG) to register a first number BC TO  representing the total number of datapackets stored in said buffer means and a second number BC i  representing the number of datapackets of said connection stored in said buffer means and calculating means (CALC) to calculate said ratio proportional to said number of datapackets of said connection BC i  and inversely proportional to said total number of datapackets BC TO .